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We take measures now, for tissues where prions are a possible transmission risk. The article mis-represented that. But: (1) there are only so many resources to

• travisoneill1 8y ago
  The example in the article has very little transmissive ability because it grows in the brain and eyes. If there were a respiratory prion disease that could be much different. By nature of being a protein they are simpler and harder to eliminate than bacteria or viruses: > In a particularly vexing twist, prions are also nearly impervious to destruction, even when attacked using a strenuous combination of disinfectants, heat, and pressure.
  • dahfizz 8y ago
    > If there were a respiratory prion disease that could be much different. Not really. The point your parent is making is that prions themselves don't reproduce like viruses and bacteria. Its basically impossible for a large scale breakout to occur and spread.
    • DennisP 8y ago
      But they do reproduce, by causing other proteins to misfold. If they didn't reproduce at all, then ingesting a few prions wouldn't cause any problems. They can't reproduce outside of the body, but neither can viruses.
      • jamiek88 8y ago
        Yes but they can only warp their own specific kind of protein not take over an entire reproductive ability of the native cell. It’s orders of magnitude less reproduction.
    • ergothus 8y ago
      Can you explain why? I'm not saying this is wrong, but they definitely replicate (by encountering and warping other proteins), so are you (and grandparent) saying that the replication rate is too slow? If so, why? Are you saying we have no means of transmitting proteins? (that sounds wrong, though I've been wrong before) From my (ignorant, despite being interested in prions for decades now) perspective, you have something that (1) can replicate, (2) is durable (3) is harmful, and only the relative rarity of prions in general (because 1 and 3 are physically unusual to combine) have kept them from being a general problem. As we tinker with DNA and thus look into creating new proteins and factors that would influence protein-folding, I'd think it's worth taking the matter seriously (though not fear-mongering), certainly as part of our need to understand proteins better anyway. What are my faulty assumptions?
      • PeterisP 8y ago
        A prion can't arbitrary replicate from "food" or "host", its replication is more like a damaged version of protein X that can damage that same protein X if it encounters it. In many aspects it stays the same protein - the exact same DNA, the exact same sequence, just folded differently. A virus can overtake a cell and mobilize its resources to create a bajillion copies of that virus. A prion can transform only as much copies of that protein as that cell has made in its normal processes.
        • ergothus 8y ago
          A bacteria replicates at a much smaller rate than a virus. A virus requires a cell to replicate, bacteria require a much more limited range of hospitable environments. Both bacteria and viruses "attempt" to create exact copies, just as a prion does. Admittedly prion replication probably has more accuracy, but that prions occur at all indicates the process allows for natural selection. These don't seem to put prions outside of the "replication" category - they replicate by encountering other proteins, so they are in a body. Their rate of replication is limited (or boosted) by the rate of encountering these proteins. They attempt to create copies of themselves with the chance of failure or different end result.
    • deleted 8y ago
      [deleted]
  • nonbel 8y ago
    How is this at all a "twist"? The reason you cannot deactivate prions using these methods is that they are meant to denature protein. Prions are "amyloids"/beta-sheets, which means they are already in the lowest-energy state. This lowest-energy-state is exactly why the presence of prion can serve as a nucleation point for other proteins to denature into beta-sheets.
    • travisoneill1 8y ago
      I don't care whether or not it's a "twist". I care that there is an entire class of pathogen that we don't know how to sterilize a surface of.
      • nonbel 8y ago
        You just use bleach and then autoclave: >"combining autoclaving (even at 121 degrees C) with a sodium hydroxide treatment is extremely effective." https://www.ncbi.nlm.nih.gov/pubmed/10658760 https://www.ncbi.nlm.nih.gov/pubmed/10658760
        • coryrc 8y ago
          Bleach is sodium hypochlorite; sodium hydroxide is lye/caustic soda.
          • nonbel 8y ago
            Yea, sorry. Earlier in the abstract it mentioned sodium hypochlorite then I didnt read closely: "Strong sodium hypochiorite solutions achieve inactivation but other chlorine-releasing compounds are less effective" Usually there is some sodium hydroxide in standard sodium hypochlorite bleach solution as well though, perhaps that explains why they reported it is the most effective of the chlorine bleaches.
      • arkades 8y ago
        It’s been said a few times in this thread that that is a misrepresentation by the article. Allow me to quote at length from an article on the topic by Brown and Lee: One of the characteristic features of prions is their resistance to a number of normal decontaminating procedures. These pathogens are resistant to processes affecting nucleic acids, such as hydrolysis or shearing [9]. However, agents that digest, denature, or modify proteins do have activity against prions [7]. The PrP purified from the brains of scrapie-infected animals (PrPSc) can be inactivated by prolonged autoclaving (at 121ºC and 15 psi for 4.5 hours), or immersion in 1N NaOH (for 30 minutes, repeat three times), or immersion in concentrated (>3 M) solutions of guanidine thiocyanate [10]. However, certain cautions prevail; it appears that inadequate autoclaving can establish heat-resistant subpopulations that fail to diminish with a further cycle of autoclaving [11]. Stainless steel instruments also may retain infectivity even after treatment with 10 percent formaldehyde [12,13]. Newer decontamination techniques are being investigated. There has been some success in sterilization using a combination of sodium dodecyl sulfate (SDS), proteinase K, and pronase [14]. A radio-frequency gas-plasma treatment has been shown to effectively decontaminate surgical instruments [15]. Another group has tested a decontamination formula combining copper metal ions with hydrogen peroxide [16].
  • kurthr 8y ago
    If any of the proteins involved in respiration were susceptible to lower free energy confirmations (different foldings that were entropically favorable in vivo) then they likely would already be present, there would be such a prion and life that used those proteins would be highly selected against. Respiration is very common in animals. As it is, very few proteins in humans have alternate favorable form (by luck or selection?). The exception appears to be the extremely complex and relatively new nervous system of mammals. I'd guess that our immune systems might be another place to look, but that is very highly tested. Frankly, this seems like a susceptibility that is rare because it is chemically odd not that there is a lack of potential exploitation. Luckily, the range of creatures that share our respiration system far exceeds the range of creatures which share our recently evolved nervous system.
• zaarn 8y ago
  Nitpick but the step between virus and prion is a viroid; a naked piece of RNA. They mostly exist in plants to my knowledge and are basically the smallest possible infectious disease. The smallest viroids clock in at around 120 base pairs (240 nucleotides).
  • tossandturn 8y ago
    Prions are like gamma-induced bit flips, Viroids are like small code patches, and Viruses are self-deploying code patches.
    • jvanderbot 8y ago
      What blows my mind is these aren't really analogies, they are in fact mostly truth.
      • thinkpad20 8y ago
        To be precise, these aren’t really analogies, they are in fact similes. :)
        • kenbellows 8y ago
          To be precise, similes are a type of analogy
  • selimthegrim 8y ago
    What's a virion? https://www.theguardian.com/society/2018/dec/10/mysterious-paralyzing-illness-children-record-total-cdc https://www.theguardian.com/society/2018/dec/10/mysterious-p...
    • arkades 8y ago
      A virion is the singular noun for a viral particle. The viral genetic material plus capsid equal an individual virion.
    • 8y ago
• nwallin 8y ago
  > (2) prions will never be a wildfire plague. They have little or no tranmissive ability, by nature of being absolutely naked protein. Chronic wasting disease (CWD) (affects deer) can be transmitted by infected saliva. One of the symptoms of symptoms of CWD is excessive saliva production. It is very transmissible, and is devastating captive populations of deer, although it is relatively rare in the wild. I think if a similar TSE affected humans, spreadable by infected saliva, it would absolutely be a wildfire plague. https://en.wikipedia.org/wiki/Chronic_wasting_disease https://en.wikipedia.org/wiki/Chronic_wasting_disease
  • arkades 8y ago
    That is interesting, and new to me. I’ll have to read up on it more. Thank you for the link.
  • subroutine 8y ago
    Is there any mammalian prion disease not linked to the PRNP gene (which is fairly conserved across mammals)? At first I assumed that 'prions' came in many flavors, like virus. However from my brief lit search, it seems like people are talking about (p)rion proteins as if they were't all (P)rion proteins (PRNP). If all mammalian 'prion' disease can be traced to a single conserved gene, I think the risk of another 'prion-like' disease cropping up is pretty low. But then again, who knows? Prion disease still seems shrouded mystery, which I find odd given (1) how inherently interesting this topic seems, and (2) we've gotten really, really good at molecular biology. I feel like we are missing a key piece of the puzzle when it comes to understanding prion disease. The literature seems to want people to conceptualize the disease etiology as such: an alternately folded (disease causing) variant of PRNP protein (PrPs) bumps into a normal version of PRNP (PrPc), causing a normal copy of PrPc to also misfold into PrPs. Rinse, repeat. So you can basically think of it like an enzyme that catalyzes a conformational change on versions of itself, in a feed-forward cascade. I feel like an alternative hypothesis however, could be one of an autoimmune response. The mammalian immune system, particularly the antibody system, is mind blowing. This system can recognize virtually any foreign protein -- it can even recognize specific sub-moieties and conformations of proteins (antigens). It must, do this while never mistaking an endogenous protein to be foreign; if it does, you get an autoimmune disease. My idea is basically that PrPs is just slightly different enough from PrPc to get tagged as foreign by the antibody system (which it absolutely can do, given that we can perform western blots to detect the PrPs variant), but also just similar enough for the antibody system to mistake some endogenous PRNP for the foreign version.
• fao_ 8y ago
  > (2) prions will never be a wildfire plague. They have little or no tranmissive ability Mad Cow Disease was caused by a prion[0]. [0]:https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopathy https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopat...
  • mirimir 8y ago
    And it was spread by the livestock industry.